A liquid crystal display device of a TN (Twisted Nematic) type being widely used has high contrast but, on the other hand, has a problem of high visual angle dependence since the molecular axis of the liquid crystal rises due to the vertical electric field. Since demand for a large-sized monitor of a TV or the like is increasing in recent years, a so-called transverse-electric-field-type liquid crystal panel such as the IPS (In-Plane Switching) type or FFS type is being spread, in which an electric field substantially parallel to a substrate for which thin film transistors (hereinafter, called TFTs) are provided is applied to liquid crystal molecules to drive the molecules. A transverse-electric-field-type liquid crystal display panel of, for example, the IPS type has a plurality of pixel electrodes substantially parallel to a data line or scan line on a substrate, and a common electrode which is paired with the pixel electrodes. By an electric field substantially parallel to the substrate formed between the pixel electrodes and the common electrode, the liquid crystal molecules are turned in a plane parallel to the substrate, thereby controlling display. By driving the liquid crystal molecules in this manner, the visual angle dependency with respect to the rise angle of the molecular axis is eliminated. The visual angle characteristic is more advantageous as compared with that of the TN type.
In such a liquid crystal display device, it is preferable to drive liquid crystal molecules in a wider range. For example, patent literature 1 discloses a technique of driving a liquid crystal material in a wider area, provided as a layer between a substrate for which a TFT is provided and an opposed substrate which is opposed to the substrate and has a color filter. In the patent literature 1, for example, a technique of shortening the interval of neighboring pixel electrodes to be smaller than the limit determined by the conventional process margin and preventing short-circuit of the neighboring pixel electrodes. Patent literature 2 discloses a liquid crystal display device of a transverse electric field type with improved brightness by disposing a pixel electrode and an opposed electrode substantially parallel to a scan line, making a data line and a source pixel electrode adjacent to each other, and forming a storage capacitance electrode on the scan line (FIG. 10). On the other hand, patent literature 3 discloses s liquid crystal display device of the transverse electric field type with improved aperture ratio in which a scan line and a data line are covered with a common electrode via an interlayer insulating film.
Patent Literature 1: Japanese Unexamined Patent Application Publication No. 2004-212436
Patent Literature 2: Japanese Unexamined Patent Application Publication No. 2002-122876
Patent Literature 3: Japanese Unexamined Patent Application Publication No. 2004-062145